Study On The Mechanism Of Wireless Power Transfer Based On Magnetic Resonances

The technology of electrical equipment obtaining power from grid with non-contact way is wireless power transfer. Because there is no electrical connection between power source and load, the advantages of wireless power transmission are safety and convenience, etc.Compared with non-contact inductive charging, the distance of wireless power transfer based on magnetic resonances is longer; Compared with microwave power transmission, wireless power transfer based on magnetic resonances is omni-directional and nonradiative power transfer.In this paper, wireless power transfer based on magnetic resonances is developed, system structure, principle, process of power transmission as well as constraint equation in the process are analyzed. Theoretical model of the wireless power transfer is built used coupling-mode equations, and correctness of the model is verified experimentally.The interference on wireless power transfer is analyzed, including passive jamming and active jamming. The relationship between passive interference source and disturbance degree is studied according on different aspects, including position, size and resonance frequency. The effect of electromagnetic field emitted from active jamming with different frequency on wireless power transfer system is studied.On the basis of the study on the performance of the system, the design of wireless power transfer based on magnetic resonances is proposed for concrete load with given transfer distance and efficiency as higher as possible. Programming in Matlab, load impedance, transfer power and distance is input, and design parameters of the system is output, including resonance frequency, supply voltage and coil size, and so on. A design example is given also.